I have been playing with this a little and find cock feather to the riser on a standard 3 fletch gives me a good nose anchor and great clearance. You can rotate it some and still have great clearance on your bottom feather.
The angles I have read about for the anchor feather range from 9 o’clock to about 10:45. I think it varies with individual face structure.
I have also been playing with 4 fletch. I have all three, 60x120, 90, and 75x105, if you want to look at them and try them. The best one will depend some on your final nose feather angle. None of them will be as good as the 3 fletch for the nose anchor because they all have a feather at 180 deq. from the anchor feather. This will put that feather into the riser shelf joint or on the shelf if you anchor feather is around 10:00 or higher up. For 9:00 they all work well with a good amount of paradox, but the 60x120 and 75x105 give the most bottom feather clearance at the edge of the shelf. The 60x120 has the largest open area between feathers, but with a strong helical the 60 deg. Feathers are real close and just look odd to me. I like the 75x105 the best all around for a 4 fletch and it would work well with a 9:00 anchor feather.
In the end if you have an anchor feather around 10-11:00 and want more feather for stability than what you get with 3x4 with maximum feather clearance, I think it would be best to go to 3-5” or longer feathers.
I have a little drawings showing all the angles with different feather rotations if you want me to send a PDF of it.